Las Vegas to Denver via I-70 any tips on roads

If you want to stay at a nice State Park with hookups, check out James M Robb State Park in Fruita, CO (west side of Grand Junction). Then visit Colorado Nat'l Monument from there.

If you come back to Moab via I-70, drive on scenic Hwy 128 along the Colorado River down to Hwy 191, instead of turning off I-70 at Hwy 191.

If by 87 you mean I-25, that is a fine drive. 160 is a pretty drive and totally doable. Just be aware of Wolf Creek Pass. Road is very good, long climb, then just gear down on descent. I've never been on 491.

@G7ARYM can you elaborate on the "tire scam"?

I have heard about the climb around Vail. I have an 06 Duramax so I wasn't too worried.

We are planning at hitting KOA's along the way as they seem predictable as to what you can expect with amenities since most of the websites have good details. Any suggestions?

Last August the drive east was easy with little traffic after the heat in Vegas. Stopped in Beaver KOA but be aware of a tire scam at the truck stop at the north end of town. The climb through CO is mostly gentle until around Vail where it was nice to have a turbo diesel at altitude. You will enjoy the trip.

You are good to go. Have been on I-15 and I-70 many times.

Not sure about the others but I would expect OK.